Insensitive mutations and overexpressed detoxification genes in
diamondback moth
We used FastD-TR to detect insensitive RyR mutations in two resistant
populations, ZZ and CHR, and a sensitive population, CHS, of P.
xylostella . The results showed that the frequencies of the insensitive
mutation G4946E were 2.32%, 66.1% and 94.55% in CHS, ZZ and CHR,
respectively (Table 1 ) (30 individuals in pool,one mutated allele can be
detected in a pool containing 59 wild type alleles) . However, FastD-MR
searching showed that no detoxification gene was expressed more than
two-fold (|log2FoldChange| > 1, P-value
< 0.01) higher in the CHR population. In contrast, six
detoxification genes were overexpressed in the ZZ population
(Table 2 ). Among these genes, CYP6a2 was overexpressed
10.82-fold in ZZ population. CYP6BG1 had elevated expression
levels by 3.3-fold in the ZZ population. These genes were reported to
confer chlorantraniliprole resistance (X. Li, Li, Zhu, Gao, & Liang,
2018). Our results indicated that both the insensitive RyR mutation
G4946E and six overexpressed detoxification genes contribute to the
resistance to chlorantraniliprole in P. xylostella populations.